The 4th International Whale Shark Conference

Background The Galapagos Whale Shark Project is a multi-institutional effort initiated in 2011 with the aim to characterize the presence, population structure and movement patterns of whale sharks within and around the Galapagos Marine Reserve. This specific study aimed to understand their occurrence, residency and habitat use around Darwin Island, located at the northern tip of the Galapagos Archipelago, where large individuals had been reported to be seasonally abundant. Approach This study followed a diversified methodology approach that included: analysis of a local underwater visual census database of pelagic species (2007–2013) to establish seasonality in their occurrence; specific whale shark surveys (2011–2013) to collect information about shark's size (laser photogrammetry), sex, behavior and signs of potential pregnancy; photo-ID records (2011–2013) obtained during these surveys to determine residency and abundance; and the deployment of acoustic tags for continuous tracking around Darwin Island to assess habitat use at the study site. Results Whale shark presence at Darwin Island follows a seasonal pattern. During the cool season (July–December), a strongly female-biased whale shark population, composed mostly (91.8%) by large individuals (11.35 m ± 0.12 m (TL ± SE)), pass through the study site. The great majority of these individuals show clear distended bellies, which could be a sign of a potential pregnancy. Population dynamics models for these apparently pregnant sharks estimated the presence of 3.76 ± 0.90 (mean±SE) sharks in the study area per day with an individual residence time of 2.09 ± 0.51 (mean±SE) days. Assuming constancy in these rates for the entire cool season, we can estimate a net abundance of 695 ± 166 (SE; 95%CI 442–1110) apparently pregnant whale sharks per season. Movement patterns analysis of four apparently pregnant individuals revealed an intense use of Darwin's Arch, where no feeding or specific behavior has been recorded or could be inferred from their dive profiles, together with periodic excursions around the island's vicinity. Sharks showed a preference for intermediate depths (20–30 m) with occasional dives mostly to mid-water, remaining the majority of their time at water temperatures between 24–25°C. Conclusions The lack of evidence of specific behavior observed at Darwin Island, together with the short residence time and strong intra-seasonal abundance and high turnover rate, indicate that this location is not an aggregation site but an important stopover in a migration. In the case of adult R. typus individuals observed, this migration might involve reproductive purposes, as all but one were apparently gravid.

Background Whale shark tourism is increasingly popular at coastal predictable aggregations around the world. However, only one description accounts for provisioning of whale sharks (Rhincodon typus), which is at Oslob, Philippines, where sharks are provisioned between 6 am and 1 pm daily within a demarked tourist interaction area. Understanding the potential effects of provisioning on the behaviour of this species is important for their conservation. Approach To investigate whether whale shark diving behaviour was affected by the provisioning, four whale sharks with known extended residency at the study site were tagged with CEFAS G5 temperature-depth-recorder (TDR) tags. Three individuals were juvenile males with estimated total lengths of 4.5, 5.0 and 6.5 m (P-432, P-480 and P-403 respectively), and a fourth individual was a juvenile female measuring 5.5 m (P-385). A Hawaiian-sling spear pole was used to deliver stainless steel anchors with a tether carrying a swivel 10 cm into the subdermal layer of the whale sharks on the ventral side between the first dorsal fin and the first lateral ridge. Three TDR tags were randomly deployed amongst the individuals over a period of 18 months. Linear mixed effect models were used to test how attendance at the provisioning site affected shark depth use and variability. Results Tags were deployed for an average duration of 49.5 provisioned days (sharks present daily at the site) and 33.8 non-provisioned days (sharks were absent from the site). The deepest dive was recorded by P-403 to 1,251 m, at a minimum temperature of 12.1 °C. The tags revealed a pronounced shift in habitat use by individuals when away from the provisioning site. Specifically, during provisioned days, time spent at the surface (0 – 2 m) between 6 am and 1 pm was ca. six times longer than during non-provisioned days. During provisioned days, deep dives occurred mostly near or at the end of the provisioning activities (i.e. 10 am to 2 pm), whereas on non-provisioned days, deep dives occurred mostly between 4 am and 10 am. This shift could suggest that whale sharks have a need to thermoregulate following a prolonged period of time at the surface where temperatures regularly exceed 31 °C. Conclusions The use of TDR tags on whale sharks revealed modified diving behaviour at Oslob, a unique provisioning site. This behavioural modification should be considered when developing guidelines for sustainable tourism and conservation measures for the species.

Background A large aggregation of whale sharks in the central part of the Arabian/Persian Gulf has recently been documented by the Qatar Whale Shark Research project. Observations made by offshore workers have indicated a continuous presence of whale sharks close to platforms in the Al Shaheen oil field during the summer months. It has been established that the sharks come here to feed on fish eggs of the Mackerel tuna, Euthynnus affinis. The Al Shaheen location is characterized by numerous offshore platforms that could attract the spawning Mackerel tuna and thereby influence the numbers and distribution of whale sharks in the area. Understanding the movement and residency patterns of whale sharks is critical for their management, particularly in an offshore oil field. Approach In the period from 2012–2015 a total of 104 whale sharks were fitted with acoustic V16 tags. The sharks were all tagged in the Al Shaheen oil field during the aggregation period from May to September and ranged in size from 4 to 10 meters TL. The movement pattern of sharks within the Al Shaheen field was monitored using an array of up to 15 VR2W receivers placed a minimum of 4 km apart. The receivers were placed on the seabed at different distances from selected offshore installations and recovered using remotely activated releases. Results Of the 104 tagged sharks, 102 were detected by the deployed receivers during the study period. The maximum detection distance was estimated to be between 500–1000 m from the receiver. More than 99% of the detections occurred between the months of April–September. Average annual residence time in the Al Shaheen area was 38.5 days (±27.5 SD) with some sharks showing a continued presence during the entire April–September period. Conclusions The results indicate that the whale sharks are almost only present in the Al Shaheen area during the April–September period, confirming the visual observations made by workers on the offshore installations. Aggregations, sometimes numbering more than 100 individuals, have only been observed while the whale sharks were feeding on Mackerel tuna spawn. The long residence time indicates that the Al Shaheen area is a highly important feeding ground. The sharks showed a high affinity for the same platforms throughout the study period, while their presence was only rarely recorded at other platform locations. This could indicate that the Mackerel tuna are spawning in a confined location within the study area and that the whale shark distribution within Al Shaheen is strongly associated to the spawning site and the prevailing currents. The platforms themselves may concentrate whale shark presence in the spawning area, but their full importance for the behavior of whale sharks is still to be determined. Mitigating measures have been established in order to minimize potential impacts on whale sharks related to offshore activities.

Background Prior to 2001, due to the lack of legal protection, whale sharks were brutally and extensively hunted across the shores of Gujarat state in western India. Wildlife Trust of India (WTI) actively lobbied the Ministry of Environment and Forests (MoEF), Government of India, for legal protection of the species by placing it in Schedule I of the Wildlife (Protection) Act, 1972. Approach A brief survey during 2004 along the coastal town of Veraval, the hub of the whale shark slaughter, revealed a low awareness level (19%) of poaching and the protection status of whale sharks among the fishers. Following the survey, WTI launched a large-scale whale shark awareness campaign in 2004, with a special focus on Veraval, with the funding support of Tata Chemicals Ltd (TCL), which led to the training of 1500 fishers into an organised information providing network. Results The whale shark campaign spread awareness on the plight of the species and its protected status in Gujarat. The campaign not only helped convert Gujarat fishermen into protectors of the whale shark by bringing about a major change in the perception and attitude of local people, but also helped in local protection of the species. As a result of the campaign, seven coastal towns adopted the whale shark as their city mascots. The campaign led to a model relief programme that offered monetary support to fishers whose nets were damaged or had to be cut open during the rescue and release of whale sharks. To speed up the release and reduce stress on the sharks, a self-photo documentation process of whale shark rescue for fishers was started. 1200 waterproof cameras were distributed to fishers to document the rescue and release of whale sharks. The captured images of a rescue by fisher folk served as evidence to prove the damage to nets. The photos also helped fishermen claim financial relief from the government scheme to repair/replace nets. From its inception until 2015, 571 whale sharks had been rescued and voluntarily released by fishers with not a single record of whale shark slaughtering. To further strengthen the whale shark conservation activities among fishers, fourteen “Vahlino Mitro” clubs (Vahlino Mitro =Friends of whale sharks) were registered in the fishing villages of Veraval and Mangarol (seven clubs each), with an objective of motivating fishers to fish in a whale shark friendly manner, and to make coastal school children understand the importance of coastal ecosystems and involve them in action based programmes related to whale shark conservation. This project has won several conservation laurels. These include the Bombay Natural History Society (BNHS) Green Governance Award in 2005, the Gujarat Ecology Commission (GEC) Award during 2012 and the UNDP Indian Biodiversity Award to the Gujarat Forest Department for co-management in 2014. Conclusions The whale shark conservation project with the support of fishing communities and corporate house has stopped the killing of whale sharks along the Gujarat coast. The project also instilled a sense of pride among fishing communities along Gujarat coast and ongoing annual International whale shark day celebrations and Gujarat whale shark celebrations are keeping the whale shark conservation message alive among the communities and coastal school students.

Background The conservation of whale sharks, like other endangered species, requires, among others factors, an understanding of the effects that variability in habitat have on long-term species viability. In the Mexican Northern Caribbean, a Habitat Monitoring Program for the whale shark was established in 2005 to describe the spatio-temporal variability of environmental data and whale shark distribution. Approach From 2005–2014, when whale sharks were present in the region (May to September), monthly trips were made to record whale shark sightings and hydrological data (sea surface temperature, salinity and dissolved oxygen). Water samples were collected to determine nutrients (nitrite, nitrate, ammonium, silicates and phosphates), as well as chlorophyll-a (Chl-a) and zooplankton biomass. We compared the environmental variables at sites with and without whale sharks present. Maps of zooplankton biomass were produced for each year in order to explore their relationship with the distribution and abundance of whale sharks. Results Areas with high whale shark abundance have been identified inside the study region. At these sites the whale shark feeds, taking advantage of the abundance of zooplankton, as a result of two events: the intensity of the Yucatan upwelling and the presence of dense masses of fish eggs. The whale shark aggregation areas influenced by the upwelling were characterized by high Chl-a concentrations (mean±SE 0.9±0.4 mg/m3), high nutrients and mixed zooplankton in which several groups were present (usually copepods were the most abundant group). In the whale shark aggregation area called “Afuera”, the zooplankton samples were dominated by fish eggs. This area registered significantly higher zooplankton biomass (mean±SE 3356.1±1960.8 mg/m3) in comparison with that recorded in upwelling areas (mean±SE 103.5±57.2 mg/m3). Zooplankton biomass was the most influential environmental variable to determine whale shark abundance, supporting the close relationship between this species and their food availability. Spatio-temporal changes in distribution and abundance of whale sharks have been recorded in the region, as well as changes in their food availability. Conclusions The whale shark uses selected areas within the Mexican Caribbean. These areas have different hydrobiological characteristics. Changes in distribution and abundance of whale sharks inside the study area may make it more difficult to implement suitable management strategies. We need more data to understand the reason for these changes, for example increased knowledge about the ocean circulation patterns at this site and other factors that may influence and characterize spawning inside the aggregation area. The continuity of hydrobiological monitoring is key to ensure the integrity of this critical habitat.

Background The Red Sea has received little study when compared to other areas. This holds true for sharks in general and for whale sharks in particular. The discovery of a seasonal aggregation off the Saudi Arabian coast has made the targeted study of Red Sea whale sharks more feasible. Assessing the size and structure of this aggregation is a first step toward understanding the basin-scale population within the Red Sea and how that population fits into the wider Indian Ocean. Approach Photo-ID records were collected from 2010 through 2015. These were analyzed and fit to several population models. The most parsimonious model was then used to describe the aggregation. Demographic data, including the size and sex of individual sharks was collected and compared to reports from other aggregations. Size was visually estimated to the nearest half-meter and sex was determined by the presence or absence of claspers between the pelvic fins. Results From 2010 to 2015, 305 encounters with whale sharks were recorded within the aggregation. From these, 267 suitable photos were used to identify 136 individuals. Sharks were divided evenly between the sexes and the distribution of sightings showed no evidence of sexual segregation. All individuals were immature based on size estimates and, in males, juvenile clasper morphology. An open population model was found to best represent the data and estimated a daily abundance between 15 and 34 whale sharks during the aggregation season, with local residence times ranging from 4 to 44 days. Residence times away from Shib Habil ranged from 15 to 156 days with a permanent emigration/mortality rate between 0.07 and 0.58 individuals per year. Conclusions These results are broadly similar to those from other aggregations of R. typus, although the observed sexual parity and integration found at this site are unique for the species and need further study.

Background Ch'ooj Ajauil AC, a non-profit organization created in 2010 involving tour operator and external research collaborations, is devoted to monitoring and preserving marine pelagic life in the Mexican Caribbean. The organization explored the question, how many whale sharks are been damaged by tourism boats? Approach Six years of methodic registration of scars, injuries and abrasion on whale sharks, using video and photographs, conducted by 3 snorkelers alternating with up to 5 surface observers on board a research boat, along 150 transects, observing 1336 whale sharks, in waters off north east Isla Mujeres, México, where the largest aggregation has been reported. Results Whale shark tourism began over 15 years ago in north Quintana Roo, México on the north east coast of the Yucatan peninsula. Tour operators have been stigmatized as the ones responsible for whale shark injuries, regardless of the multiple other boats transiting the area, including commercial fishers, private yachts and huge vessels. Scars on whale sharks come from many sources including other shark bites and smack and graze, but the most conspicuous ones are propeller cuts and mutilations, mostly on the dorsal fins and body. It is hard to determine geographically where an injury happened, or when. Previous reports on the same population at a different zone, estimated between 13 – 33% of total sharks as injured. There have been statements from the public observers suggesting that up to 50% of the sharks show some kind of scars. This shark meta-population moves into other areas across a large region, including the Gulf of Mexico, the Caribbean Sea and open Atlantic waters. Actual estimations indicate that 29.64% of the whale sharks show some kind of abrasion, including healed and old scars; while less than 5% presented fresh injuries per year. Conclusions No avoidance behavior toward boats was observed from the scarred sharks or from the freshly injured, but the latter were found to be more cautious around snorkelers. Whale sharks with fresh propeller cuts did not modify their site fidelity. Boating enforcement should be improved in order to keep damage to the species at lowest rate possible. A note on healing and recovery is given to document the rapid process of this on some animals.

Background Examples of aggregations of large Chondrichthyes are well known worldwide and occur mostly in response to seasonal increases in prey abundance. In the Maldives, whale sharks, Rhincodon typus, are thought to have a semi-annual residency pattern, moving west from December to April and east from May to November. However, an important aggregation of predominantly immature male whale sharks seems to be persistent all year round throughout the South Ari atoll region. Understanding residency patterns of this aggregation as well as inter-atoll movements is fundamental to determine the drivers of aggregation, and to design effective conservation management plans at a regional and national scale. Approach The present study used mark-recapture photo identification of whale sharks sightings collected from 2006 to 2015 in the Republic of Maldives. For the aggregation analysis, the Maldives Whale Shark Research Programme (MWSRP) in collaboration with 52 stakeholders and citizen scientists, members of the Big Fish Network (BFN), provided over 3000 sightings, across the South Ari Marine Protected Area (S.A.MPA). Generalised linear models were used to determine seasonality patterns and the effect of environmental variables. Maximum likelihood population models were fitted to establish the size and residency patterns of the aggregation. Results Through the close collaboration between MWSRP and the BFN, 271 individual whale sharks were successfully identified. At a regional scale, as in most whale shark aggregations worldwide, the South Ari aggregation is mainly composed of immature males (86% of the sexed individuals). However, despite a large seasonal variation in sea surface temperature, primary productivity, wind speed and direction, the lag identification rate did not show any significant seasonal pattern. Population models revealed that the aggregation could be characterised as an open population, with an average of 15 sharks present at any given time. Our findings also imply that whale sharks visit the aggregation for a mean of four years and during that time stay for around two of every six weeks. Conclusions South Ari atoll aggregation shows unprecedented levels of residency and site fidelity. Despite showing size and gender structures similar to other aggregations around the world, this aggregation is remarkable because there is no seasonal peak in sightings. It remains to be investigated if this is a due to aperiodic ocean climate phenomena (as in Tofo, Mozambique) or if sharks are aggregating in response to drivers different than feeding. For instance, exploitation of an undetected food source in adjacent deep waters, and subsequent thermoregulation might account for the observed residency patterns. In conclusion, our findings have important implications for the improvement of the conservation management of this symbolic species in the Republic of Maldives, where it is largely targeted by an unregulated tourism industry.

Background The impact that pollutants have on whale sharks (Rhincodon typus) is a question that remains largely unexplored. Whale sharks (WSs) are known to aggregate seasonally in different areas in the Gulf of California. Although this species is protected in Mexico since 2001, habitats for most of these aggregations are not protected. Out of the 7 localities were they aggregate, 3 are protected whereas the other 4 need to have some protection. Urban and touristic developments are major threats to their habitats because they lead to mangrove and estuary damage, both being important areas for their food resources. Moreover, due to poor fishery regulations, whale sharks often die as by-catch in fishing nets. The growth of tourism in the area of La Paz and Los Cabos represents an increase in maritime traffic and, thereby an increase in the number of collisions of WSs with boats. Finally, the increasing human activity in WS grounds is the cause of chemical pollution from urban waste waters, vessels, agriculture and solid waste (it is common to see WSs feeding while surrounded by marine litter). Approach In this work, we perform the first ecotoxicological investigation, using skin biopsy, of whale sharks sampled in the Gulf of California. In order to evaluate the potential impact of anthropogenic activities on this species, 13 skin biopsy samples were collected in January 2014 from 12 males and 1 female whale shark in La Paz Bay. PCBs (twenty-one ortho PCB congeners), DDTs (six o,p'- and p,p'- DDE, DDD and DDT isomers), PBDEs (fourteen congeners from tri- to deca-substituted) and HCB were analyzed on freeze-dried blubber biopsy samples by GC-qMS. Biomarker responses (cytochrome P450 1A, CYP1A1) were detected, using western-blotting (WB) techniques, in integument biopsies (skin tissue samples) of this vulnerable (IUCN) species. Semi-quantitative analysis was performed for each WB using Quantity One software (Bio-Rad, 1-D Analysis Software). Results The average abundance pattern for the target contaminants was PCBs >DDTs > PBDEs >HCB. Mean concentration values (and ranges) of 8.42 (0.720–41.40) ng/g w.w. were found for PCBs, 1.31 (0.20–6.36) ng/g w.w. for DDTs, 0.294 (0.02–1.14) ng/g w.w. for PBDEs and finally 0.192 (0.01–0.66) for HCB. The detected values are lower than in other planktivorous shark species (e.g. basking shark) in other areas (e.g. Mediterranean Sea). Cytochrome P450 1A (CYP1A1) was also detected for the first time, using western-blotting techniques, in the skin samples of this species. The potential impact of microplastic (plastic fragments smaller than 5 mm) and related contaminants (such as plastic additives) has also been explored in this large filter feeding species. Preliminary data on the average density of microplastics in the superficial zooplankton/microplastic samples collected from the Sea of Cortez (La Paz Bay) showed that the values ranged from 0.00 items/m3 to 0.14 items/m3; furthermore, concentrations of mono-(2-ethylhexyl) phthalate (MEHP), used as a tracer of plastic additives, ranged from 13.08 ng/g to 13.69 ng/g. Conclusions Further ecotoxicological investigation on whale shark skin biopsies will be carried out in order to support the idea of the usefulness of non-lethal approaches in the worldwide ecotoxicological risk assessment of this vulnerable species.

Background The use of citizen scientist contributions is a cost-effective approach that can provide valuable information, usually at scales larger than those attainable by individual researchers. The challenge, however, is to motivate contributors to continuously supply data when doing so can be time consuming and monotonous and where the results of the contributions they make are part of long term studies with infrequent outputs. When studying a highly mobile animal in a geographically disparate location such as the Maldives, a widely spread network of contributors submitting encounter information on whale shark (Rhincodon typus) sightings is vital to providing information on spatial movements and residency patterns. Approach The Maldives Whale Shark Research Programme created a prototype of a mobile device friendly version of the identification software I3S and linked it to an established, custom made interactive online portal called the Big Fish Network, designed to provide a platform for data exchange. Tour operators were invited to submit standardised data logs from their excursions. In return, operators were openly provided access to a photo-identification database of whale shark individuals and 8 years of corresponding encounter data. Outputs from the portal for the operators include an interactive map, a customised trip report, social-media bulletins and a mobile app. These features were designed to aid tour guides in planning and marketing their excursions and informing and engaging tourists, during and after the excursion. Results Since the launch of the Big Fish Network in July 2013, 834 stakeholder data submissions were received from external contributors; equivalent to 59.8% of the total encounters recorded in the same period, as compared to 23.4% between April 2006 and July 2013. In addition, utilising this network produced evidence for 5 instances of inter-atoll movements using sightings submitted from locations that are outside the main survey areas. Conclusions We believe that this example of using appealing technology and open data as tools to produce carefully tailored incentives may strengthen stakeholder commitment to citizen science initiatives and increase the catchment of data from a wider range of stakeholders. Employing similar models at a regional level in whale shark hotspots around the world may improve data flow to global databases for this species.